1. Field of the Invention
The present invention relates to a manipulator for operating a distal-end working unit through power transmitting members.
2. Description of the Related Art
According to endoscopic surgery (also called laparoscopic surgery), it is customary to form a plurality of holes or incisions in the body surface (abdomen or the like) of the patient, insert trocars (tubular instruments) into the respective incisions as instrument passage ports, and introduce tip ends of forceps having shafts through the respective trocars into the body cavity to perform the surgical operation on the affected part of the body. Working units such as a gripper for gripping a living tissue, scissors, the blade of an electrosurgical knife, etc. are mounted on the tip ends of the forceps.
The endoscopic surgical operation performed with forceps requires the surgeon to be trained in advance because the working space in the body cavity is small and the forceps need to be operated using the trocars as fulcrums. Since the forceps that have been used heretofore have no joints in the working unit on the tip end thereof, the forceps have a small degree of freedom and the distal-end working unit of the forceps can be operated only on an extension of the shaft. Therefore, cases that can be handled under the usual training practice for endoscopic surgery are limited to a certain range, and the surgeon need to be trained and skilled to a considerably high level in order to be able to perform endoscopic surgery on various other cases not in the limited range.
Attempts have heretofore been made to improve conventional forceps and develop forceps having a plurality of joints in a working unit thereof (see, for example, Japanese Laid-Open Patent Publication No. 2004-105451). The developed forceps, which may also be referred to as a manipulator, is free of the limitation and difficulties of the conventional forceps, can be operated with easy techniques, and can be applied to a wide variety of cases.
The manipulator comprises a working unit having a distal-end working unit (also referred to as an end effector) mounted on the distal end of a slender shaft. The main body (operating unit) has actuators for actuating the distal-end working unit through wires. The wires are wound around respective pulleys in the proximal end portion of the working unit.
There has been proposed a medical robot system including such manipulators movable by robot arms (see U.S. Pat. No. 6,331,181, for example). The medical robot system can be remotely controlled by an operating unit which comprises a joy stick and a master arm and can be operated in various patterns under programmed control. The medical robot system has a plurality of robot arms that are selectively used to perform respective surgical techniques. One of the robot arms supports an endoscope for capturing an image in a body cavity which is to be confirmed on a display monitor.
The manipulator tends to be smeared with the blood and body fluids of the patient while a surgical technique is being performed on the patient. Therefore, the manipulator needs to be cleaned and sterilized after the surgical technique has been performed.
However, since the distal-end working unit of the manipulator has a plurality of joints, the blood and body fluids of the patient are likely to flow into the manipulator through the joints. As it is tedious and time-consuming to clean the manipulator, it has been desired in the art that the manipulator be of a structure which can easily cleaned and sterilized. Particularly, the blood and body fluids may possibly find their way from the distal-end working unit deeply into the slender shaft through which the wires extend and also occasionally into the main body of the manipulator. If the blood and body fluids have entered the slender shaft and the main body, then it is more tedious and time-consuming to clean the manipulator.